1. Field of the Invention
The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition suitably used for a lithography process which is performed in the production process of a VLSI, a high-capacity microchip and an imprint mold structure, and the like and for other photofabrication processes, and an actinic ray-sensitive or radiation-sensitive film and a pattern forming method each using the same. More specifically, the invention relates to a positive type resist composition where an electron beam, an X ray, or EUV light is used which is preferably applied in the process described above and a resist film and pattern forming method which use the same.
2. Description of the Related Art
In micromachining using lithography, recently, along with the high integration of integrated circuits, there has been demand for ultra fine pattern formation of the order of several tens of nanometers. Along with this demand, a trend of shorter wavelengths is able to be seen where the exposure wavelength changes from g-rays to i-rays and further to KrF excimer laser light. Furthermore, currently, other than excimer laser light, development in lithography where an electron beam, an X ray, or EUV light is used is also progressing.
In addition, micromachining using a resist composition is not only directly used in the manufacturing of integrated circuits but has also been applied recently to the manufacturing of a so-called imprint mold structure and the like (for example, refer to JP2004-158287A, JP2008-162101A, and “Science and New Technology in Nanoimprint”, edited by Yoshihiko Hirai, Frontier Publishing (published in June 2006)).
In particular, lithography where an X ray or EUV light is used is positioned as the next generation or a more advanced generation of pattern forming technology and a positive type resist with high sensitivity and high resolution is desired. In particular, higher sensitivity is an extremely important issue in order to reduce the wafer processing time, but when higher sensitivity is pursued, not only is there a reduction in the resolving power but there is a deterioration in line edge roughness and development of a resist which satisfies all of these properties is strongly desired. Here, line edge roughness refers to that an edge appears uneven when a pattern is viewed from directly above since an edge of the pattern of the resist and the interface with the substrate changes in a manner which is not regular in a direction which is perpendicular to the line direction due to the properties of the resist. In particular, line edge roughness is an extremely important issue for improvement in an ultra fine region. High sensitivity, high resolution, excellent pattern formation, and excellent line roughness are in a tradeoff relationship and the means by which all of these are satisfied is extremely important.
As a method which solves these problems, the use of a resin, which has a structural moiety where an acid is generated due to the irradiation with actinic rays or radiation (below, “photo-acid generator”) in a main chain or a side chain of a polymer, is being considered (for example, refer to JP1997-325497A (JP-H9-325497A), JP1998-221852A (JP-H10-221852A), JP2007-197718A, WO06/121096A, JP2009-93137A, US2007/117043A, JP2008-133448A, JP2006-259509A, and Proc. of SPIE Vol. 6923, 692312, 2008)
Among these, for example, a ternary copolymer of hydroxystyrene, an acrylate containing an adamantyl group, and an acrylate containing a photo-acid generator is disclosed in US2007/117043A and Proc. of SPIE Vol. 6923, 692312, 2008.
In addition, a resist composition, which contains resin which is sensitive to high energy rays or heat and has a repeating unit which generates a sulfonic acid in an end of a side chain containing fluorine, is disclosed in JP2008-133448A to improve the high resolution, the density bias, and the exposure margin.
In addition, a resist composition which contains a resin, which includes a repeating unit with a sulfonium cation structure as the repeating unit which has the acid-photo generating group in the side chain, and a composition, which generates sulfonic acid, bis(alkylsulfonyl)amide, or tris(alkylsulfonyl)methine due to irradiation with actinic rays or radiation is disclosed in WO06/121096A.
However, in particular, in lithography where an electron beam, an X ray, or EUV light is used, the actual state of affairs is that there is a demand for further improvements in the sensitivity, resolution, pattern formation, and line edge roughness.